Injection molding apparatus provided with internal plasticizing capsule

ABSTRACT

An injection molding apparatus of the type in which a piston moves a mass of material along a cylinder toward a nozzle and in which there is an internal plasticizing capsule within the cylinder which has a plurality of internal balls held in place therein so that the plastic material must be forced through the capsule and pass through the interstices between the balls, thereby thoroughly mixing the material and raising its temperature by friction to assist in plasticizing the same. The balls are held within the capsule in an arrangement which includes a large ball at each end of the capsule, there being an opening at each end, and a ring of smaller balls holding each large ball in place, the capsule being removable from the cylinder and capable of being disassembled to release the balls and permit ready cleaning.

United States Patent 72] Inventor Georg Nusstein FOREIGN PATENTS Munich, Germany 742,209 12/1932 France 259 pp 636,715 1,226,047 2/1960 France 259 [22] Filed May 8,1967 [45] patented Jam 12, 1971 Primary Exa n1merRobe11 W. Jenkms [73] Assignee Firm: Georg Seidl Anomey sllverman & Cass Munich, Germany [32] Priority May 14, 1966 [33] Germany [31] $103,818

ABSTRACT: An injection molding apparatus of the type MOLDING APPARATUS Which a piston moves a mass Of material along a WITH INTERNAL PLASTICIZING CAPSULE toward a noz zle and In wh1ch there is an Internal plasticizu capsule within the cylinder whlch has a plurallty of lntem 9 Claims, 3 Drawing Figs.

balls held in place there1n so that the plastlc material must I U-S. forced through the capsule and pass through the interstic l Cl /02 between the balls, thereby thoroughly mixing the material ar Field of Search 259/4, 18, raising its temperature by f i ti to assist in plasticizing t} 36, 2 same. The balls are held within the capsule in an arrangeme1 which includes a large ball at each end of the capsule, the {56] References Cited being an opening at each end, and a ring of smaller balls h0l( UNITED STATES PATENTS I ing each large ball in place, the capsule being removable fro1 2,583,206 1/1952 Borck 259/4 the cylinder and capable of being disassembled to release t1". 2,584,827 2/1952 Bailey 259/4 balls and permit ready cleaning.

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INJECTION MOLDING APPARATUS PROVIDED WITH INTERNAL PLASTICIZING CAPSULE BACKGROUND OF THE INVENTION This invention relates generally to injection molding apparatus and more particularly is concerned with apparatus in which there is an internal removable capsule in the injection cylinder through which the plastic material is forced during molding for homogenizing and heating such material.

The injection molding machine is well-known as such and mass is available at the injection nozzle.

In prior structures, the mixing and heating of the mass being 20 forced forward by the piston has, at least in part, been effected by means of baffle devices installed in the cylinders between the piston and the nozzle. One known device of this kind consisted of a torpedo or capsule which was in the form of a cylinder having a plurality of small axial holes formed therein, 25

thus requiring the mass to be compressed ahead of the capsule and thereafter extruded through the axial holes. Several disadvantages attached to this form of structure.

Such capsules are expensive to manufacture because each must have the plurality of axial holes bored throughout its length. These holes additionally are difficult to clean when changing from one material to another, especially where the colors of the respective materials are different. Furthermore, this form of baffle device provides substantially less frictional heat than required satisfactorily to plasticize many plastic materials, thereby requiring additional heating means for the apparatus and thus increasing the manufacturing costs of the articles being manufactured by theapparatus.

SUMMARY OF THE INVENTION The invention contemplates a novel solution to the problems which are mentioned above, and hence the principal object of the invention is to provide an injection molding apparatus which is more economical and more efficient than prior apparatus of this type.

The solution to the problems is achieved by providing a capsule inthe injection cylinder which is formed of two separable parts, each having a constricted opening at its end and being hollow so as to provide a through passageway for the materials being forced through the capsule, but there being a plurality of balls of steel or the like packed into the capsule, thereby providing a plurality of tortuous passageways for the expression of material through the capsule, this serving not only to thoroughly homogenize the materialbut also providing substantial friction to raise the temperature of the mass. This results in a highly efficient plasticizing of the material so that it may freely be injected through the nozzle into the mold.

An important object of the invention is to provide a structure as generally described above.

Still another object of the invention is to provide an injection molding apparatus which includes a hollow capsule installed internally of the injecting cylinder in the path of material being forced through the cylinder by the piston, there being a plurality of small generally rounded bodies packed into the capsule, these bodies being in contact with one another at points on their surfaces which provide a large number of interstices, and the bodies being unbound one to another so that said bodies may be .removed from the capsule and separated from one another to facilitate cleaning and the like.

Another object of the invention is to provide a capsule for. use in an injection molding machine which is formed of separable parts having a plurality of unbound bodies secured on the interior of .the capsule and providing interstices for the passage of plastic material in a tortuous manner to gene large amounts of frictional heat and to plasticize homogenize the material.

Still a further object of the invention is to provide a car of the character described in which the bodies comprise of different sizes mounted in a novel manner.

Many other advantages and objects'of the invention occur to those skilled in this art from the ensuing dlSCUSSlt which preferred embodiments of the invention are descr 10 in detail and illustrated in the accompanying drawing. M

variations in structural features and arrangement of 1 thereof may occur to the skilled artisan without depa from the scope or sacrificing any of the advantages of th vention.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMEN In FIG. 1 there is illustrated a median sectional through a capsule constructed in accordance with their tion. The capsule is designated generally by the refer character 1 and is formed as a hollow cylindrical meml having an internal chamber la which contains a plurali balls 2 of steel or other suitable material. The body 3 capsule 1 is formed of two parts 4 and 5 which are sec together by means not shown, and are readily separab provide access to the interior hollow chamber la. For e ple, a mating separable joint 3a enables axial separation c two parts 4 and 5 approximately at the center of the l Each end face of the respective parts 4 and 5 is provided a relatively large coaxial opening to enable the passage c plastic material through the capsule during use thereof. 'l openings are defined by annular flanges 6 which provide an internal shoulder 6a for a purpose presently tr described.

The left hand opening 7 is the inlet port and the right opening 8 -is the outlet port for the passage of material thr the capsule from left to right.

Through the use of a large number of small balls 2, a tively large number of interstices 2a is formed providing 1 rality of tortuous passageways for movement of ma through the capsule. The ports 7 and 8 are each blocked relatively large ball 9, each being supported by a rii smaller balls 9a seated against the respective annular s ders 6a. In this manner, the balls 9 form closures to retai internal balls 2 in place so that these latter balls may be d ly packed and provide a considerable surface for gene: high frictional temperatures, without the danger of fallin; Likewise, the spherical surfaces presented to the openi and 8 promote easy flow into and out of the capsule l.

The Size of the balls 2, 9a and 9 and their relative dian may be adjusted experimentally for the physical propert the different materials being processed by the use of the sule l.

In FIG. 2 the capsule l is shown associated with an inje molding machine, being installed internally thereof. cylinder 10 of the molding machine provides an enlargl temal cylindrical chamber 10a within which the capsul disposed. There is a cylindrical compression chambr opening into the chamber 10a, coaxially aligned wit opening 7 and preferably having the same diameter as t 75 temal diameter of the flange 6 so that materials pressed chamber 11 by movement of the piston 12 will readily :er the chamber la without interference by the left end of cylindrical member 3. The materials to be plasticized are roduced into the compression chamber 11 to the right of piston by any conventional means (not shown). The right hand end of the capsule is preferably enlarged at to form a shoulder 16a which engages against the flange 1 formed on the end of the cylinder 10, thereby properly ting the capsule within the chamber 10a. An end cap 15 ring a central nozzle 15a is screw-threaded onto the flange 1 by means of cooperating threads indicated at 14. A conipassageway 18 formed coaxially of the end cap 15 con- :ts the outlet port 8 with the nozzle 15a to lead the sticized material from the capsule to the mold 13. The er is shown in diagrammatic representation. t will be appreciated that during operation, movement of piston 12 from left to right forces the materials to be sticized into the capsule 1, and into the assembly of balls 2 itained in the hollow chamber la.'The multiplicity of in- ;tices, extending not only axially, but radially in all actions, thoroughly mixes the materials and produces con- :rable heat due to friction. This temperature increase ists materially in plasticizing materials, and inthe case of tain other materials, such as rubber, shortens the time uired for vulcanization in a later step. This step is espelly favorable in the manufacture of pieces having thick lls. lhe capsule is readily disassembled from the injection lding machine by unscrewing the end cap 15 to expose the 1ged end 16 protruding from the cylinder 10. Any suitable ling device enables the entire capsule 1 bodily to be hdrawn from its seated condition in the chamber 10a. For imple, the flange 16 may be threaded at 17 on its periphery, l the pulling tool (not shown) under such circumstances ild have a nut or other part which is screwed onto the age to enable the withdrawing force to be applied. After noval, the parts 4 and are separated and this releases all of balls which are easily manipulated out of the two parts and aned, or replaced, if desired. I lhe construction of the capsule l is quite simple while being y effective and highly efficient. The only parts which need made specially are the parts 4 and 5, balls being commerlly available in practically any desired sizes. The capsule may be used in many kinds of injection molding chines and in the performance of many different kinds of Iding. The bodies need not be balls, although these are per- )8 the most economical, but might have any different metric shape, providing they are capable of being packed lsely into the hollow body 3 and will provide the tortuous sageways. The novelty of the structure is enhanced by virof the fact there is no bond between the bodies, all of them ng independent and hence easily assembled into the cap- 2. Nonetheless, when the parts 4 and 5 of the capsule body are connected together, the bodies combine to form a yrinth or multipassage baffle through which the plastic terial is forced, and which results in a thorough mixing and igh temperature being produced in a relatively short axial tance. In certain structures it might be desirable to use era! of these capsules in a cylinder, .coaxially arranged ng a chamber similar to that shown in FIG. 2 at a, but of use longer. In this type of structure, the end flange l6 uld be eliminated, and other means used to seat the interior lsule or capsules, and to withdraw the same when desired. 'hus in FIG. 3, the molding machine 20 has a chamber 22 in the cylinder 24 with two capsules 26 and 28 therein, these having the construction of the capsule l, but without the end flange 16. End cap 30 holds the capsules in place. The remainder of the structure is obvious.

It is believed that the invention has been sufficiently described to enable the skilled artisan to understand and practice the same. The invention has been distinctly pointed out in the appended claims intended to be broadly and liberally construed.

I claim:

1. A capsule for installation internally of an injection molding apparatus within the cylinder of such apparatus, comprisa. a hollow cylindrical member providing an internal chamber and having end ports to enable plastic materials to be expressed through the interior of the body;

b. a plurality of bodies disposed within said cylindrical member;

i. said bodies being in contacting engagement with one another,

ii. having configurations to provide a plurality of interstices through which the said plastic material may pass in a tortuous path, I

iii. said bodies being of at least two different sizes, there being a first smaller size interior of the capsule and the second larger size disposed at the said end ports; and

c. means being provided for securing said'bodies within the cylindrical member. g 2. The capsule of claim 1 in which the bodies comprise balls.

3. The capsule as claimed in claim 2 in which said member is formed of two parts secured together to retain said capsule and balls in assembly, but separable in an axial direction to enable removal of said balls.

4. The capsule of claim I in which said end ports are coaxial openings. 7

5. The capsule of claim 1 in which the bodies are balls, and there is a single ball of said second larger size disposed in each of said end ports with certain others of said smaller balls arranged in cooperative position relative to said larger size balls to constitute said certain others and said single balls said securing means. i

6. The capsule of claim 5 in which said securing means include flanges surrounding said end ports to seat said certain other smaller balls in said cooperative position.

7. A capsule as claimed in claim 1 in which said bodies comprise balls, said ports comprise circular coaxial end openings, with one opening at each end of said'member, said balls comprise a plurality'of small interior balls, and a pair of large balls, said securing means including internal annular seating means about each said opening, therebeing a ring of smaller balls seated against each seating means of diameter substantially smaller than the diameter of said large balls, and one each of said pair being respectively secured internally of said rings of smaller balls and against said ring.

8. The capsule of claim 7 in which said'member is formed of a plurality of parts capable of disassembly in an axial direction.

9. The capsule as claimed in claim 1 in which said member is formed of two parts secured together to retain the capsule and bodies in assembly, but separable in an axial direction to enable removal of said bodies from said member independently of one another. 

2. The capsule of claim 1 in which the bodies comprise balls.
 3. The capsule as claimed in claim 2 in which said member is formed of two parts secured together to retain said capsule and balls in assembly, but separable in an axial direction to enable removal of said balls.
 4. The capsule of claim 1 in which said end ports are coaxial openings.
 5. The capsule of claim 1 in which the bodies are balls, and there is a single ball of said second larger size disposed in each of said end ports with certain others of said smaller balls arranged in cooperative position relative to said larger size balls to constitute said certain others and said single balls said securing means.
 6. The capsule of claim 5 in which said securing means include flanges surrounding said end ports to seat said certain other smaller balls in said cooperative position.
 7. A capsule as claimed in claim 1 in which said bodies comprise balls, said ports comprise circular coaxial end openings, with one opening at each end of said member, said balls comprise a plurality of small interior balls, and a pair of large balls, said securing means including internal annular seating means about each said opening, there being a ring of smaller balls seated against each seating means of diameter substantially smaller than the diameter of said large balls, and one each of said pair being respectively secured internally of said rings of smaller balls and against said ring.
 8. The capsule of claim 7 in which said member is formed of a plurality of parts capable of disassembly in an axial direction.
 9. The capsule as claimed in claim 1 in Which said member is formed of two parts secured together to retain the capsule and bodies in assembly, but separable in an axial direction to enable removal of said bodies from said member independently of one another. 